The present invention relates to automatic mounting and dismounting apparatus of attachments.
Various apparatus for automatically mounting and dismounting an attachment to and from a spindle head having a rotatable spindle, or to and from the end surface of a ram have been proposed. Among these prior art apparatus is a clamping device which clamps the attachment through a collet as disclosed in the Japanese Laid Open Patent Specification No. 85839 of 1985. A clamping rod contacting the inner side of the collet is shifted, at the time of expanding the collet, so as to increase the diameter of the collet in a stepped opening of the collet to withdraw the collet toward a ram. At the time of unclamping, the clamping rod is shifted, or the diameter of the collet is reduced, thereby effecting the automatic mounting and dismounting of the attachment.
A problem associated with the device disclosed in the Laid Open Japanese Patent Specification, described above, is that it is of the type in which when the clamping rod is shifted, it is necessary to provide a clamping rod shifting mechanism. Therefore, the construction of the automatic mounting and dismounting apparatus is complicated.